The invention relates to a corona-effect sound emitter.
Known sound emitters of the type under consideration normally operate with a modulated corona discharge which generates air pressure fluctuations and usually provide for a tone of remarkable clearness.
Corona-effect sound emitters are disclosed, for example in the French Pat. No. 1,041,790 and U.S. Pat. Nos. 2,768,246 and 3,177,288. The known sound emitters however, although provided with metal shielding can not prevent propagation of electromagnetic waves outside the emitter housing.
The transformer disposed in the vicinity of the high frequency oscillator generates in operation electromagnetic waves, and although the whole device is located inside of the metal shielding to prevent propagation of electromagnetic waves outside the shielding it can happen that electromagnetic waves can leak outside via electrical connecting leads which pass necessarily through the metal shielding. These disturbing electromagnetic waves can be further suppressed by selected self-induction and condensation in electrical leads although this measure can not totally prevent leakage of electromagnetic waves through the electrical leads. If leakage of electromagnetic waves is about 100 microvolts it can totally disturb the function of the household appliance, particularly a television set.